The top two floors of the ageing Pata department store in Bangkok are occupied by a zoo. More than 200 species of animal are kept in small cages with concrete floors. Big cats like tigers and leopards continually pace around their tiny enclosures, while monkeys and apes are made to perform and pose with visitors.

A petition to free the zoo's only gorilla has attracted more than 36,800 signatures. Bua Noi (Little Lotus) has been on display at the zoo since 1987.

Bua Noi, the zoo's only gorilla, lies on the concrete floor of her enclosure at the Pata ZooTaylor Weidman/Getty ImagesPata Zoo's director insists Bua Noi is healthy emotionally and physicallyTaylor Weidman/Getty ImagesThe zoo is located on the 6th and 7th floors of the ageing Pata Department Store in BangkokTaylor Weidman/Getty Images

The campaign to find a better home for the aged gorilla is led by Sinjira Apaitan. She said: "I don't think animals should be locked up in such [an] unnatural habitat. I hope to help all other animals being held captive in this high-rise zoo as well."

However, the owners of the zoo are fighting back. Pata Zoo director Kanit Sermsirimongkhon warned: "Don't use mob rule here." He said his zoo has a licence and its hygiene standards meet all existing legal requirements.

Manop Praditwongsin, a vet at the zoo, said concrete floors could be healthier for animals; if Bua Noi was moved to an enclosure with real soil, she could face the risk of bacterial infection.

Bua Noi has been kept in a cage on top of the Pata shopping centre since 1987Taylor Weidman/Getty Images

Getty Images photographer Taylor Weidman took these pictures of animals at the Pata Zoo.

An orangutan mother and her baby lie on the concrete floor of their enclosureTaylor Weidman/Getty ImagesA visitor has her picture taken with an orangutanTaylor Weidman/Getty ImagesA leopard takes a break from pacing around its small enclosure at the top of the Pata department storeTaylor Weidman/Getty ImagesA chimpanzee begs for treats while an orangutan looks onTaylor Weidman/Getty ImagesAn albino macaque is seen in a cage in the department store's zooTaylor Weidman/Getty ImagesA black-capped capuchin looks out from a cageTaylor Weidman/Getty Images